Beef Cattle Lice
External parasites of beef cattle are many. One often neglected, is lice. Both chewing and bloodsucking lice are more abundant during winter. They may be present during summer and fall but large infestations occur rapidly in winter and spring.
Watch for signs of scratching and rubbing against solid objects. Chewing lice feed on hair, scabs, and excretions of cattle. Infestations weaken the animal, interrupt normal feeding patterns, and make them more susceptible to disease. Sucking lice feed on blood by piercing the hide with their sharp mouths. This loss of blood can stunt growth and reduce weight gains. Sucking lice are usually found on the head, neck, and withers, around the tail head, and on inner surface of legs. They are prevalent in our county.
To control cattle lice, use approved pesticides applied through sprays, backrubbers, dust bags, pour-ons, and injectables. Read the labels carefully, and follow directions and withdrawal times. Never apply famphur (Warbex) or fenthion (Lysoff, Tiguvon) as pour ons during October, November, or December, unless earlier applications were made of these for grubs. Never apply ivermectin; either as pour-on, or injectable, during October, November, or December, as grub related reactions can occur. Cattle treated with ivermectin in August, and September can be retreated during winter for internal parasites, mange mites, and lice, without the danger of grub related reactions.